The invention concerns in particular, although not exclusively, grape harvesting machines, and will be described more particularly in connection with this type of harvesting, although a machine including the harvesting device according to the invention can equally be used to harvest other fruits and berries, for example blackcurrants, gooseberries or raspberries, or olives or coffee beans.
The principle of harvesting grapes is practically the same in most modern harvesting machines. It is a question of shaking the vine by imparting to it a sinusoidal or pseudo-sinusoidal movement of a certain amplitude and frequency adapted to detach the grapes or the bunches of grapes. This movement is communicated to the whole of the vine by shaker members disposed to operate either on the stocks or the stems of the vines or on the vegetation, i.e. on the fruit-bearing area of the vine, depending on the type and number of shaker members used. The percentage of the bunches of grapes and/or grapes that are detached from the vine depends on the number and the amplitude of the oscillations to which a given bunch of grapes is subjected. The more vigorously a given bunch of grapes is shaken, and the greater the number of times it is shaken, the greater the chance of said bunch or its individual grapes being detached from the vine. The number and the amplitude of the oscillations to which a given bunch of grapes is subjected depend on various parameters for which suitable values can be selected, in particular the amplitude and the frequency of the output of the drive mechanism associated with the shaker members, the length of the active area of said shaker members, their stiffness or flexibility, and the rate at which the machine moves forward, and on other factors that are imposed by the vine itself, in particular how it is trained, its shape and the resistance that it opposes to the movement of the shaker members.
In particular, the number of shaker members and the height of each of them must be adjustable to match them to the height of the vines to be harvested. Thus, for low-growing vines, two or three pairs of shaker members appropriately distributed over the height of the vine are used, for example, whereas for tall vines five or six pairs of shaker members suitably distributed over the height of the vine are used, for example. As the vines planted in adjacent lots or in adjacent rows of vines in the same lot sometimes have different heights from one lot to the other or from one row of vines to the other, the user of the harvesting machine may be obliged to modify the number of shaker members and/or to adjust their height several times a day, before starting to harvest the next lot or the next row of vines. It is therefore desirable for it to be possible to adapt the shaker members to suit the vines to be harvested conveniently and quickly.
In some prior art harvesting machines including a harvesting device of the type defined above (see FR-A-2 605 487, for example), the drive means for each shaker assembly include an oscillating vertical plate which is rigidly connected to the corresponding oscillating vertical shaft and to which the first end of each shaker member, which is in the form of an arcuate rod, is detachably attached. To this end, each oscillating vertical plate is provided with a series of pairs of holes, the pairs of holes being spaced vertically and the two holes of each pair being spaced horizontally. The first end (usually the front end) of each shaker member, which is in the form of an arcuate rod, includes two holes having a spacing corresponding to that of a pair of holes in the corresponding oscillating vertical plate and is coupled to the latter by means of two clamps that surround the front end of the rod and which are fixed by two screws or two bolts inserted in the two holes of a selected pair of holes in the oscillating vertical plate. In prior art machines currently in service, one of the two clamps, to be more precise the one between the front end of the rod and the oscillating vertical plate, is made in the form of a reinforcing member that extends horizontally towards the rear over a part of the length of the rod and which curves outwards. At the rear, the chassis of the harvesting device includes two vertical legs and the second end (usually the rear end) of each shaker rod of each shaker assembly is connected to the chassis by a link that is articulated by a vertical pin to a yoke that is itself fixed against the inside face of one of the two vertical legs by means of two nut-and-bolt fasteners that pass through a selected pair of holes of a series of pairs of holes provided in said vertical leg.
Under the above conditions, each time that a shaker member must be taken out of service, it is necessary to unscrew four bolts (one pair of bolts at the front end and one pair of bolts at the rear end of the shaker member), to remove the two pairs of bolts from the two pairs of holes in which they were inserted in the oscillating vertical plate and in the vertical leg of the chassis, and to then extract the shaker member and the associated link from the machine completely and put them down on the field or remove them to some other place. Each time that a shaker member must be put into service, it is necessary to feed it with the associated link into the interior of the machine, then to position the front and rear ends of the shaker member at the required height, then to engage the two bolts of each of the two pairs of bolts in the respective two pairs of holes in the oscillating vertical plate and the vertical leg of the chassis that correspond to the required height for the shaker member, and finally to replace and tighten the four nuts on the four bolts. Similar operations are also effected each time that the height of a shaker member must be adjusted, except that in this case the shaker member does not need to be removed from the machine. As modifying the number of shaker members or adjusting their height generally involves at least one pair of shaker members, and usually several pairs of shaker members, it is obvious that the above operations are irksome and time-consuming.